1. The SUN!

2. Basic Facts Mass M = 2x1030 kg = 300,000ME
Radius R = 7x108 m = 7x105 km = 111RE
Mean Density = Mass/Volume = M/((4/3)R3)= 1400 kg/m3 = 1.4 g/cm3
Distance = 1.5x1011 m = 1.5x108 km = 8.3 light-minutes
Luminosity L = 3.9x1026 W (Solar Constant = 1350 W/m2)
Mean Surface Temperature = Teffective = 5780 K
Composition By Mass By Number
H ~68% ~90%
He ~31% ~10%
“Heavies” ~1% ~1%

3. The Sun Contains 99.8% of the Mass of the Entire Solar System!

4. We Rely on the Sun for…

5. …
Source of energy
Plants-photosynthesis
Creates wind
Water cycle

6. The Sun’s Atmosphere

7. Photosphere All elements are gaseous
Get denser as you move toward the core
Photosphere is the “surface” we can see

8. Granulation

9. Chromosphere Density decreases but temperature increases
Oddity considering the rest of the sun decreases in temperature as you move away from the core

10. Spicules
Flamelike jets of gas that rise up into the chromosphere

11. The Corona Outermost part of the Sun’s atmosphere
Extends millions of miles into space

12. Reading

13. Solar Activity

14. Magnetic Field

15. Video

16. Sunspots What are they? Cause Regions marked by lower temperatures
Dark spots on the solar surface
Cause
Magnetic field exits one and enters the other
Messes up convection in granules and causes cooling

17. Structure
Umbra-dark region
Penumbra-lighter surrounding region

18. History 1610 Sunspots were first observed by Johannes and Fabricius
1612 Galileo explained sunspots

19. How They Are Used Rotation of the Sun Weather? Low sunspot activity
High sunspot activity

20. Little Ice Age Low solar activity-few sunspots 1645-1715
Frozen rivers and year-round snow in unlikely places

21. Sunspot Cycles
Cycles every 11 years

22. Maunder Minimum
Lowest point of solar activity

23. Prominences
Magnetic field redirects the flow of the gases-out one and in the other

24. Coronal Mass Ejection
Causes on Earth

25. Solar Winds Flow of charged particles away from the sun Continual
Greater at coronal holes and less at helmet streamers

26. Fusion